Most of the axial growth of the eye occurs during the first two years of life. While the growth of the eye is usually precisely regulated by a process known as emmetropization, this process can become deranged in certain conditions resulting in excessive or retarded axial growth and large refractive errors. This project seeks to elucidate the molecular mechanisms responsible for the physiological processes that cause aberrant ocular growth with aphakia. Specifically, we will assay infantile eyes for changes in certain neurotransmitters and growth factors after removing the crystalline lens which we have previously shown retards ocular growth. Understanding the mechanisms whereby aphakia alter ocular growth is of vital importance in order to accurately select the most appropriate intraocular lens power to implant into infantile eyes after cataract surgery. In addition, by understanding the mechanisms retarding ocular growth, it may be possible to modulate the excessive ocular growth which occurs in certain pathological conditions such as retinopathy of prematurity.